Referring to FIG. 1, a conventional nail gun 1 includes a gun body 11, a muzzle 12 formed at a front portion of the gun body 11, a first safety member 13 movably mounted to the muzzle 12, a second safety member 14 movably mounted to the gun body 11, and an adjusting assembly 15 interconnecting the first and second safety members 13, 14 and located at a lower portion of the gun body 11. The adjusting assembly 15 includes a rotary member 151. Rotation of the rotary member 151 drives movement of the first safety member 13 relative to the second safety member 14 in a nail-firing direction (Z) so as to adjust an extent by which the first safety member 13 projects out of the muzzle 12. By such, the conventional nail gun 1 is capable of driving nails (not shown) into an object by different depths.
However, since the adjusting assembly 15 is located at the lower portion of the gun body 11 and since the rotary member 151 is operated in a manner of being rotated, operation of the rotary member 151 is inconvenient, and is easily hindered by the gun body 11.
Another conventional nail gun disclosed in U.S. Pat. No. 6,988,648 includes first and second safety members, a thumb post that co-movably mounted to the first safety member, and a thumb wheel rotatable to drive movement of the thumb post so as to drive movement of the first and second safety members relative to each other for adjusting the depth-of-drive. However, operation of the thumb wheel is similar to the rotary member 151 in FIG. 1, and is inconvenient.